BIDDEFORD, Me. — When Kylie Galliani started at the University of New England in August, she was given a key to her dorm, a class schedule and something more unusual: a $480 bicycle.

“I was like, ‘A free bike, no catch?’ ” Ms. Galliani, 17, a freshman from Fort Bragg, Calif., asked. “It’s really an ideal way to get around the campus.”

University administrators and students nationwide are increasingly feeling that way too.

The University of New England and Ripon College in Wisconsin are giving free bikes to freshmen who promise to leave their cars at home. Other colleges are setting up free bike sharing or rental programs, and some universities are partnering with bike shops to offer discounts on purchases.

The goal, college and university officials said, is to ease critical shortages of parking and to change the car culture that clogs campus roadways and erodes the community feel that comes with walking or biking around campus.

“We’re seeing an explosion in bike activity,” said Julian Dautremont-Smith, associate director of the Association for the Advancement of Sustainability in Higher Education, a nonprofit association of colleges and universities. “It seems like every week we hear about a new bike sharing or bike rental program.”

While many new bike programs are starting up, some are shutting down because of problems with theft and vandalism. The program at St. Mary’s College in Maryland was suspended because bikes were being vandalized.

“Ours was one that was totally based on voluntary taking care of the bike,” said Chip Jackson, a spokesman for St. Mary’s, “and I guess that was maybe a tad unwise. So the next generation of this idea will have a few more checks and balances.”

At Ripon, and the University of New England, officials say that giving students a bike of their own might encourage them to be more responsible. Ripon’s president, David C. Joyce, a competitive mountain biker, said the free bike idea came in a meeting about how to reduce cars on campus.

The college committed $50,000 to the program and plans to continue it with next year’s freshmen. Some 200 Trek mountain bikes, helmets and locks were bought, and about 180 freshmen signed up for the program. “We did it as a means of reducing the need for parking,” Dr. Joyce said, “but as we looked at it from the standpoint of fitness, health and sustainability, we realized we have the opportunity to create a change.”

The University of New England here in Biddeford had a similar problem — too many cars, not enough space and a desire to make the campus greener. So it copied the Ripon program, handing out 105 bikes in the first week of school. Because of the program, only 25 percent of freshmen brought cars with them this year, officials said, compared with 75 percent last year.

“We felt the campus could devolve to asphalt parking lots, and a lot of people didn’t want that to happen,” said Michael Daley, head of the university’s environmental council and a professor of economics.

The bikes are marked with each student’s name.

“I don’t have to fill it with gas, and it doesn’t hurt the environment,” said Kaitlyn Birwell, 18. “With a car, you need a parking permit, gas, and it breaks down. I’m a college student and don’t have the money for that.”

Michelle Provencal, 18, said she hopes her bike will help her avoid a dreaded side effect of being a college freshman. “Maybe instead of gaining the freshman 15 I’ll lose it,” Ms. Provencal said.

When Mercer University in Macon, Ga., asked for donations of old bikes, it received 60, which are being fixed up and painted orange and black, the university colors. Forty are available for weeklong rentals, and Mercer has organized mass rides to downtown Macon, about three miles away, to promote the program.

“A lot of students haven’t ridden a bike since middle school or even younger, but when they get back on it their faces light up,” said Allan J. Rene de Cotret, director of the program. “So why not leave your car parked where you live or back home with your parents and ride your bike around campus?”

Emory University has partnered with Fuji Bikes and Bicycle South, a local bike shop, to provide 50 bikes that can be rented at no charge at six spots on campus. Students can also buy Fuji bikes at a discount and receive a free helmet, lock and lights from Emory.

Students, faculty and staff can go to a rental station, show their Emory ID and check out bikes. The program plans to add 70 more bikes and four checkout points in the next year. In addition, about 150 bikes have been sold through the partnership in the past year, said Jamie Smith, who runs the program, called Bike Emory.

Bikes at some campuses were treated as toys rather than transportation. Others were difficult to maintain or were not used.

“The kids weren’t taking care of the bikes, leaving them wherever instead of parking them in the bike racks,” said John Wall, a spokesman for Juniata College in Huntingdon, Pa., which eliminated its two-year-old bike-sharing program this year. “The other problem was that the bikes weren’t the greatest to begin with. They were donated by Wal-Mart, and others were rehabbed. They had also been out in the weather. It just didn’t work out.”

The elements are a concern at other universities as well. More than 150 students at the University at Buffalo signed up for a city bike-sharing program that has drop-off points on campus, but it suspends service from November to April.

“It’s hard to maintain all the bikes during winter, and usage drops dramatically,” said Jim Simon, an associate environmental educator at Buffalo.

Here at the University of New England, officials wonder what will happen when snow starts falling, but they are looking toward bike-sharing programs in cities like Copenhagen and Montreal as proof that they can work in the cold.

St. Xavier University in Chicago this month is unveiling the first computer-driven bike sharing system on a college campus.

Students can wave their ID card over a docking port. The port is attached to a rubber tube, which can be used as a lock and opened by entering an access code. Students must enter the bike’s condition before it can be unlocked. The system is used in Europe, but with credit cards.

The first 15 minutes are free, and users pay 60 cents for each additional 15 minutes, or $2.40 per hour. All 925 resident students automatically become members through their ID cards. The system was intended to be environmentally friendly, with solar panels powering the ports.

A tracking system similar to G.P.S. will keep tabs on the bikes.

“You can’t throw it in Lake Michigan,” said Paul Matthews, the university’s vice president for facilities management, “because we’ll know if you throw it in Lake Michigan.”